README.md

TypeGraphQL

Motivation

We all know that GraphQL is great and solves many problems we have with REST APIs, like overfetching and underfetching. But developing a GraphQL API in Node.js with TypeScript is sometimes a bit of a pain. Why? Let's take a look at the steps we usually have to take.

First, we create all the GraphQL types in schema.gql using SDL. Then we create our data models using ORM classes, which represent our db entities. Then we start to write resolvers for our queries, mutations and fields, but this forces us to first create TS interfaces for all arguments, inputs, and even object types.

Only then can we actually implement the resolvers using weird generic signatures and manually performing common tasks, like validation, authorization and loading dependencies:

The biggest problem is redundancy in our codebase, which makes it difficult to keep things in sync. To add a new field to our entity, we have to jump through all the files - modify an entity class, the schema, as well as the interface. The same goes for inputs or arguments. It's easy to forget to update one piece or make a mistake with a single type. Also, what if we've made a typo in field name? The rename feature (F2) won't work correctly.

Tools like GraphQL Code Generator or graphqlgen only solve the first part - they generate the corresponding interfaces (and resolvers skeletons) for our GraphQL schema but they don't fix the schema <--> models redundancy and developer experience (F2 rename won't work, you have to remember about the codegen watch task in background, etc.), as well as common tasks like validation, authorization, etc.

TypeGraphQL comes to address these issues, based on experience from a few years of developing GraphQL APIs in TypeScript. The main idea is to have only one source of truth by defining the schema using classes and some help from decorators. Additional features like dependency injection, validation and auth guards help with common tasks that normally we would have to handle ourselves.

Introduction

As mentioned, TypeGraphQL makes developing GraphQL APIs an enjoyable process, i.e. by defining the schema using only classes and a bit of decorator magic.

So, to create types like object type or input type, we use a kind of DTO classes.
For example, to declare Recipe type we simply create a class and annotate it with decorators:

Then we can create queries, mutations and field resolvers. For this purpose we use controller-like classes that are called "resolvers" by convention. We can also use awesome features like dependency injection and auth guards:

I encourage you to give TypeGraphQL a try and experiment with. If you have any questions, you can ask on gitter. If you find a bug, please report it as an issue on GitHub. If you have any interesting feature requests, I would be happy to hear about them.

Support

TypeGraphQL is an MIT-licensed open source project. This framework is a result of the tremendous amount of work - sleepless nights, busy evenings and weekends.

It doesn't have a large company that sits behind - its ongoing development is possible only thanks to the support by the community.

Gold Sponsors 🏆

Please ask your company to also support this open source project by becoming a gold sponsor and getting your company logo on our README on Github as well as on the landing page of the official documentation site with a link to your company site.